SCO asks Unix licensees to certify compliance

The SCO Group has sent a letter to its 6000 licensed Unix customers, asking them to certify within 30 days that they are in compliance with all Unix source code agreements and that they are not using any code from SCO's Unix properties in Linux.

The company has sent a second letter has been sent to the Fortune 1000 companies in the US, outlining SCO's copyright claims under the Digital Millennium Copyright Act.

The letter to the Fortune 1000 contains a list of copyrighted application binary interfaces over which SCO claims copyright; Linux creator Linus Torvalds refuted these claims when the letter was published on a website last year.

The letter to licensees warns that if they do not provide "a full and complete certification" in 30 days, SCO may examine legal remedies, including termination of the license.

In March last year, SCO filed a billion-dollar lawsuit against IBM, for "misappropriation of trade secrets, tortious interference, unfair competition and breach of contract."

In May, SCO claimed that Linux was an unauthorised derivative of Unix and warned commercial Linux users that they could be legally liable for violation of intellectual copyright. SCO later expanded its claims against IBM to US$3 billion in June when it said it was withdrawing IBM's licence for its own Unix, AIX.